package com.cai310.freemarker.directive;

import java.io.IOException;
import java.io.Writer;
import java.util.Map;

import freemarker.core.Environment;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;

@SuppressWarnings("rawtypes")
public class OverrideDirective implements TemplateDirectiveModel {

	public final static String DIRECTIVE_NAME = "override";

	public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body)
			throws TemplateException, IOException {
		String name = DirectiveUtils.getRequiredParam(params, "name");
		String overrideVariableName = DirectiveUtils.getOverrideVariableName(name);

		TemplateDirectiveBodyOverrideWraper override = DirectiveUtils.getOverrideBody(env, name);
		TemplateDirectiveBodyOverrideWraper current = new TemplateDirectiveBodyOverrideWraper(body, env);
		if (override == null) {
			env.setVariable(overrideVariableName, current);
		} else {
			DirectiveUtils.setTopBodyForParentBody(env, current, override);
		}
	}

	static class TemplateDirectiveBodyOverrideWraper implements TemplateDirectiveBody, TemplateModel {
		private TemplateDirectiveBody body;
		public TemplateDirectiveBodyOverrideWraper parentBody;
		public Environment env;

		public TemplateDirectiveBodyOverrideWraper(TemplateDirectiveBody body, Environment env) {
			super();
			this.body = body;
			this.env = env;
		}

		public void render(Writer out) throws TemplateException, IOException {
			if (body == null)
				return;
			TemplateDirectiveBodyOverrideWraper preOverridy = (TemplateDirectiveBodyOverrideWraper) env
					.getVariable(DirectiveUtils.OVERRIDE_CURRENT_NODE);
			try {
				env.setVariable(DirectiveUtils.OVERRIDE_CURRENT_NODE, this);
				body.render(out);
			} finally {
				env.setVariable(DirectiveUtils.OVERRIDE_CURRENT_NODE, preOverridy);
			}
		}
	}

}